Arduino hot tub gas heating system

Hello,
I am currently making a hot tub gas heating system I would like to use a propane burner under a copper coil to heat my hot tub water I will use a solenoid valve with a relay to supply the propane gas the problem I am dealing with is the gas ignition system, I would like to use a cooker igniter to ignite the gas again using a relay to control it was wondering if anyone knew the code required to only have the igniter come on to light the gas when the valve is opened and stop the ignition while the gas is lit my system will constantly be measuring the water temperature and once it is at 40 degrees celsius the solenoid valve will close stopping the gas supply, once the water temperature is below 35 degrees celsius the valve will open again and gas will be supplied to be ignited by the cooker igniter

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 8 //Thermometer on pin number 8

const int GAS_SUPPLY =2;  //Gas valve relay on pin number 2
const int IGNITION =12;      //Igniter relay on pin number 12

OneWire oneWire(ONE_WIRE_BUS);

DallasTemperature sensors(&oneWire);

float Celsius = 0;
float Fahrenheit = 0;

void setup() {
  pinMode(GAS_SUPPLY, OUTPUT);
  pinMode(IGNITION, OUTPUT);
  sensors.begin();
  Serial.begin(9600);
}

void loop() {
  sensors.requestTemperatures();

  Celsius = sensors.getTempCByIndex(0);
  Fahrenheit = sensors.toFahrenheit(Celsius);

  Serial.print(Celsius);
  Serial.print(" C  ");
  Serial.print(Fahrenheit);
  Serial.println(" F");

if (Celsius > 40) digitalWrite(GAS_SUPPLY, HIGH);
if (celsius > 40) digitalWrite(IGNITION, HIGH);          //LOW = ON
if (Celsius > 40) Serial.print("Valve closed");        //HIGH = OFF
if (Celsius < 35) digitalWrite(GAS_SUPPLY, LOW);
if (celsius < 35) digitalWrite(IGNITION, LOW); 
if (Celsius < 35) Serial.print("Valve open");

}

Have You heard about the dot symbol...... to end a sentence and capitol letter to start the next sentence?
If the gas does not ignite directly, how will Yiu act?

What device are you using to prove the main flame is burning, so you are not releasing raw, explosive gas into the air?

JCA34F:
What device are you using to prove the main flame is burning, so you are not releasing raw, explosive gas into the air?

Was thinking about using a co2 and/or a carbon monoxide sensor or some sort of thermometer.

A free flowing,gas, not ignited, wiulde likely not be detected that way. It is the wrong way to go.
Can You tell us Your address so we can keep a safe distance to it?

hahaha. This is still very much in development the reason i came on this forum in the first place was to hear any new ideas for the ignition system (if it is even possible) what im pretty much trying to accomplish here is an automatic BBQ and it will be built the same way only with a copper coil above. It will look like a cooker hob with a copper coil above more or less.

Use a manual igniter.

Since your using a gas that is highly flammable and presents an explosion hazard in confined spaces, I recommend following strict safety practices when designing this. Don't use just "any" solenoid valve to switch the gas.

I'd look into using a proper propane gas valve/regulator. Consider a pilot-burner system with a thermopile to sense the presence of the pilot flame. Add an overtemp thermostat to the gas valve wiring to protect against things getting too hot. Use a rollout switch to ensure the flame shape is correct. Use a 24VAC transformer to power the gas valve and use a relay from the Arduino to switch the gas valve as a wall thermostat does in your home HVAC system.

Look into the wiring diagrams of gas furnaces. You want redundant safety and for the gas to be shut off if the system detects a fault.

Railroader:
Have You heard about the dot symbol...... to end a sentence and capitol letter to start the next sentence?

I thought of the same thing when the title said "Arduino Hot Tub".

Blackfin:
Since your using a gas that is highly flammable and presents an explosion hazard in confined spaces, I recommend following strict safety practices when designing this. Don't use just "any" solenoid valve to switch the gas.

I'd look into using a proper propane gas valve/regulator. Consider a pilot-burner system with a thermopile to sense the presence of the pilot flame. Add an overtemp thermostat to the gas valve wiring to protect against things getting too hot. Use a rollout switch to ensure the flame shape is correct. Use a 24VAC transformer to power the gas valve and use a relay from the Arduino to switch the gas valve as a wall thermostat does in your home HVAC system.

Look into the wiring diagrams of gas furnaces. You want redundant safety and for the gas to be shut off if the system detects a fault.

I will look into this. Thanks alot. :slight_smile:

Is your design allowing for propane gas being heavier than air?
Paul

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.